Bucket elevator



D. COLE.

BUCKET ELEVATOR. APPLICATION FILED 0150.15. l'9l4.

Patented Mar. 2, 1920.

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DAVID GQLE, 0F TUCSON, ARIZONA,

BUCKET ntnvnrere.

Application filed December 15, 1914.

To all whom it may concern.-

Be it known that 1, DAVID COLE, a citizen of the United States, residing at Tucson, in the county of Pima and State of Arizona, have invented certain new and useful Tmprovements in Bucket Elevators, of which the following is a specification.

This invention relates to endless belt bucket elevators for handling wet or dry granular material and the particular feature of novelty is the means for guiding the belt in the boot of the elevator.

Prior to my invention it has been thought necessary to make use of a so-called foot pulley for the elevator belt which placed the belt under heavy tension. As this pulley ran in the boot, a considerable amount of granular material from the overflow of the lip-going buckets found its way between the face of the pulley and the belt and hence caused cutting and abrasion of the belt, so that the life of such belts was unduly shortened.

I have discovered that it is unnecessary to tension the belt to secure sufficient tractive effort at the upper or driving pulley, and that provided the upward-moving or loaded run of the belt be guided just above the loop at the bottom of the belt, the buckets will. operate properly in the boot because of the centrifugal action imparted to the loop when the belt has the proper speed for doing the work.

My invention therefore involves the emission of the usual foot pulley and the provision of a snub pulley or equivalent guiding means ust above the boot to guide the loaded run of the belt. This allows the belt to be substantially freed of adhering granular material before it runs in contact with the pulleys.

A successful embodiment of the invention is illustrated in the accompanying drawing which shows an elevator in vertical section. the plane of section being transverse to the pulley shafts.

The elevator shaft 1 may be of any usual or preferred construction and has a boot 2 and discharge hopper 3. The drive shaft l. which is driven by any suitable means carries a belt pulley 5 and on this runs the usual belt 6 having buckets 7 of familiar form. Near the bottom of the elevator shaft 1 is a snub pulley 8, shown in transverse section in the drawing. This is placed above the lower curve or loop of the belt and so as to bear Specification of Letters Patent.

Patented Mar. 2, 1920.

Serial No. 877,415.

against the back orv inner face of the upward traveling run. of the belt. The snub pulley thus overcomes the tendency of the belt to swing backward in the boot, as the buckets strike and dig into the solid material therein. The centrifugal tendency of the belt and buckets as they swing around the lower loop causes them to strike and dig into the solid material in the boot, and a snub pulley is thus all-sufficient to hold them down to their work.

My arrangement has a number 0f definite advantages. Elevators of this general type are commonly used in metallurgical plants for elevating wet ores and pulp. When a foot pulley is used, as heretofore, mineral particles are inevitably embedded in the inner. face of the belt and these so greatly reduce the adhesion of the belt to the driving pulley that the belt must be placed under heavy tension. This prevents slipping but greatly intensifies the destructive abrasion. In my device the snub pulley is commonly above the water level in the boot so that the belt comes to it washed clean, but even in cases where the snub pulley is lower in the boot the pressure against the snub pulley not sufiicient to embed particles in the belt.

Thus the abrasion is avoided and the adhesion between the driving pulley and the belt is not impaired. v

Other equivalent guiding means might be used in place of the snub pulley shown. Its exact position may vary in particular cases, the limiting requirements being that it must be far enough down to prevent the belt from drawing away from its work under the drag of the buckets and not far enough down to exert tension upon the belt either directly or through any layer of granular material which may be interposed between them in the operation. of the device.

Obviously many structural variations are possible within the scope of the invention, and the particular embodiment shown is to be considered as illustrative and not as limiting.

The invention is confined to elevators emplovin a. relatively broad belt of leather or fabric as contradistinsguished from chain belts. In the case of chain belts, sprocket wheels are employed. and there is no diliicultv in securing the necessary driving ef fect. such as exists in the case of a flat belt running about a smooth pulley or drum. Moreover, in the case of chain or link belts the wear is negligible owing to the fact that they are of metal construction. The claims are hence to be read withthis limitation or restriction to flat belts of leather or fabric as contradistinguished from chain or link belts,

Having thus described my invention, what I claim is l 1. In a bucket elevator the combination of a boot or hopper adapted to hold material to be elevated; a suitable delivery means adapted to receive material elevated; a driving wheel; an endless flexible belt running over said driving wheel, driven by frictional contact therewith and pendent therefrom into said boot; buckets carried by said belt alternately through said boot and then up to said delivery means; and a guide pulley located wholly above the level of material contained by said boot and bearing against the upwardly moving run of said belt to limit swinging thereof under the pull of said buckets against material in said boot.

2. In a bucket elevator the combination of a boot or hopper adapted to hold material to be elevated; a suitable delivery means adapted to receive material elevated; a drivingpulley; a flat endless belt running over said driving pulley and pendent therefrom into said boot; buckets mounted on said belt and carried thereby: alternately through said boot and then up to said delivery means; and a guide pulley located above the lower loop of said 'belt so as to be incapable'of directly exerting tension on said belt but engaging the same to limit swinging thereof under the pull of said buckets against material in said boot.

3. In a bucket elevator the combination with the usual boot and delivery hopper, of a driving pulley; a foot pulley located adjacent said boot; and a normally slack elevator belt provided with buckets and running over said driving pulley and around said foot pulley, said belt and pulleys being so arranged that the belt is drawn into stressed engagement with the foot pulley only by the pull of its buckets against material in said boot.

a. In a bucket conveyer, the combination with the usual boot and delivery hopper, of a driving pulley; a belt guide located adjacent said boot; and a normally slack elevator belt provided with buckets and running over said delivery pulley and around said guide, said belt, pulley and guide being so arranged that said guide will hold the upward run of said belt against lateral movement under the pull of its buckets against material in said boot.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

DAVID COLE.

Witnesses:

L. N. PAYNE, O. L. ANDREWS. 

